Calcined Clay or Refractory clay is obtained by Calcining (heating) superior-grade Clay at high temperatures (from 850o C to 1600o C). This removes moisture and volatiles which thereby increases the Alumina content. Compared to an Alumina content of about 30% to 40% in raw Clay, Calcined Clay has an Alumina content of 40% to 60%. The Calcination is carried out in Rotary Kilns at different temperatures ranging from 850o C to 1600o C depending upon the customer's application. Product Specification Grade Name PI- 43 PI- 43(M) PI- 50 PI- 50(M) PI- 60 AL203 % 43±1 43±1 50±1 50±1 60±1 FE203 % 1.3±0.2 1.3±0.1 1.4±0.2 1.4±0.1 1.7±0.2 AP % MAX 10 6 10 6 10 BD GM/CC 2.4±0.05 2.42±0.05 2.5±0.05 2.52±0.05 2.6±0.05 PCE o/c 31-32 32-33 33-34 33-34 34-36